If I got it right, your Zappier trigger is some Mailchimp action, which creates Organization and Person in your Pipedrive contacts.
I do not have Mailchimp, but as trigger can be anything I’ve tried it with Typeform, and my Zap looked like this
To connect Organization and Person, I create Organization first, so I could use its ID in create Person
After I enabled Zap and triggered Typeform action, an Organization was created in Pipedrive and it had a newly created Person connected to it.
I hope it helps, and if does not, could you describe how are you connecting Organization and Person?